Discrimination question on ACE 350

[Thylacine]

G'day all.

I was back at the mosquito park today, found a couple of coins before the failing light and mosquitoes forced me to retreat to the car. However while I was in the park I had a play with the discrimination setting on the ACE 350, I put it in coin mode, had three bars on the sensitivity and locked out all but the last four bars of display.

I found a few coins that read from 2"-4" deep and they were all about 2" but I had a lot of deep target's I dug down to about 10" but could not find anything. This park is sodden, it was swamp that was used as a tip (rubbish dump) then the rubbish was flattened, covered with clay and sand then soil and finally grass. Would really deep targets be registering on the ACE with the settings I was using? I turned the sensitively down but I was still hitting these targets and in pinpoint mode they seemed rather large, more solid than a coin spill.

I will go back here again as it seems to be untouched by others with a detector and now that I am starting to use discrimination to filter out the trash I don't dig as many rubbish targets. On my walk back to the car I set the ACE for jewellery mode but I am yet to find anything other than pull tabs.

Thoughts?

Thylacine.

 

[NM5K]

On the ones that don't dig, try raising the coil up off the ground a few inches, and
see if it still goes off. That can sometimes help show if the object is really large or not.
IE: large cans, etc.. A coin, being small, will vanish as you raise the coil But a large
object will often still ring with the coil raised.
The depth circuit is calibrated for coins. It will be unreliable for large objects.
I don't pay too much mind to the depth reading.. I'll note it, but I don't think of the
object as automatically being at that depth. It's only really accurate for coin size
objects. Or at least with the Ace machines anyway..
IE: a quarter at 4 inches might show 4 inches, but a rusty can at 12 inches might
also show as 4 inches.. It's deeper, but large enough and conductive enough to
fool the circuit into thinking it's a quarter at 4 inches.
Some of the machines with size detection might have a better chance of telling
the difference. But the Ace machines don't have that.

 

[Woodstock]

And it's always good to remember that if it it reads 4 inches for depth and is 2 inches down that you have to take into consideration that your coil might be close to 2 inches from ground level ... therefore your reading is correct at 4 inches ... 2 off the ground and 2 in the dirt. I think that's the issue when you think your depth reading is off cause all my detectors read off when the coil isn't on the ground or almost touching it. And that's why I tend to get as close to the surface as possible, sometimes scrubbing the ground and for that you'll need a coil cover and tight connections so it doesn't give false signals. IMHO ~ Woodstock

On the ones that don't dig, try raising the coil up off the ground a few inches, and
see if it still goes off. That can sometimes help show if the object is really large or not.
IE: large cans, etc.. A coin, being small, will vanish as you raise the coil But a large
object will often still ring with the coil raised.
The depth circuit is calibrated for coins. It will be unreliable for large objects.
I don't pay too much mind to the depth reading.. I'll note it, but I don't think of the
object as automatically being at that depth. It's only really accurate for coin size
objects. Or at least with the Ace machines anyway..
IE: a quarter at 4 inches might show 4 inches, but a rusty can at 12 inches might
also show as 4 inches.. It's deeper, but large enough and conductive enough to
fool the circuit into thinking it's a quarter at 4 inches.
Some of the machines with size detection might have a better chance of telling
the difference. But the Ace machines don't have that.

 

[Dirt slinger]

Cant tell you how many "good targets" I've dug at different places with my 350 that I never actually find. Gives me a real loud, strong sounding "silver" signal at like 4-6" and I dig on down as much as 14" cuz its still giving that really good signal and still never find anything. Now I do like the above poster said when I get a real good signal, I raise it off the ground while swinging to see how high I still get the signal, if its several inches I wont even try to dig for it. I'm resolved to think its just a large, deep piece of whatever. I have a couple of socker fields here that are dirt hauled in and spread over fill. I swear I think the fill dirt must have come from an abandoned salvage yard or something cuz there are so many "LARGE" targets. In pinpoint mode some of them measure several feet across. Really? I dont think so. I wont even go back to that field because of that. I have a 2" personal max depth rule at "the fields" anyway. Maybe its buried power lines, maybe some other utilities. Frustrating though.

 

[Thylacine]

Dirt Slinger.

On the subject of large targets, not at the mosquito park but at another park that was a WWII camp I found a target with the old Master Hunter 7 ADS, it was a good solid reading but narrow and seemed to be long. So of course I dug it, 7-8" down I hit a spiral coil that I pulled out of the ground, It was a good 5'+ and it still looked good, very little corrosion and may have been from a aircraft as some of the other bits of metal I pulled up in that area were stencilled and stamped in military style. I had a feeling it may have been from the aircraft so I buried them, dusted the place down and moved on. See this story. http://www.ozatwar.com/ozcrashes/qld72.htm

BTW the crash site is next to my local RSL club (Returned Services League) and I pass the plinth placed in memory to the pilot when I am on my mountain bike as the cycle track cuts through the park.

I was hoping to go back to mosquito park this afternoon but the car has a flat battery and it is a public holiday here (May Day) so I probably won't have a chance to test out the theory of small targets and high coils until tomorrow at the earliest. Staying away from the sides of the fields has considerably reduced the number of trash targets and what I'm detecting seems to be good $1 & $2 coins. You guys should seriously think about dropping your pennies and one and two dollar bills, I am so glad we did, the majority of my coin finds are $2 coins and they are quickly adding up to a AT Pro for Xmas.

Forgot to mention I found my second gold men's ring for the year 9ct, 8g it fits my middle finger and I'm thinking of making it a keeper.

Thylacine

 

[TerraDigger]

The 350 uses a DD coil. Therefore the first 3" (approximately) from the coil bottom will many times give erroneous depth readings. This is due to the particular construct of DD coils vs a concentric coil. It is not a manufacturing defect or flaw of the unit. As suggested, raise the coil a few inches on loud signals that you think may be shallow targets. Raising the coil a few inches is also helpful to determine if it is a large (non-coin size) target.

 

[Dirt slinger]

Dirt Slinger.

On the subject of large targets, not at the mosquito park but at another park that was a WWII camp I found a target with the old Master Hunter 7 ADS, it was a good solid reading but narrow and seemed to be long. So of course I dug it, 7-8" down I hit a spiral coil that I pulled out of the ground, It was a good 5'+ and it still looked good, very little corrosion and may have been from a aircraft as some of the other bits of metal I pulled up in that area were stencilled and stamped in military style. I had a feeling it may have been from the aircraft so I buried them, dusted the place down and moved on. See this story. http://www.ozatwar.com/ozcrashes/qld72.htm

BTW the crash site is next to my local RSL club (Returned Services League) and I pass the plinth placed in memory to the pilot when I am on my mountain bike as the cycle track cuts through the park.

I was hoping to go back to mosquito park this afternoon but the car has a flat battery and it is a public holiday here (May Day) so I probably won't have a chance to test out the theory of small targets and high coils until tomorrow at the earliest. Staying away from the sides of the fields has considerably reduced the number of trash targets and what I'm detecting seems to be good $1 & $2 coins. You guys should seriously think about dropping your pennies and one and two dollar bills, I am so glad we did, the majority of my coin finds are $2 coins and they are quickly adding up to a AT Pro for Xmas.

Forgot to mention I found my second gold men's ring for the year 9ct, 8g it fits my middle finger and I'm thinking of making it a keeper.

Thylacine

Thats an interestring story, thanks for sharing. Also, congrats on the ring find.

 

[andrew9091]

Ill chime in on this....that's just the nature of the beast with the 350.....I will say I almost never take the sniper coil of my 350.....the dd coil may cover more ground but the sniper on the 350 I just like better.....keep it low and slow.....the dd coil drives me nuts at times and ay age 40 I'm gettin to old to dig holes with nothing there.........the at pro is the machine to get my gut tells me.....I like the 350 but it will drive u a little nuts....I like the sniper coil on it tho

 

[Thylacine]

andrew9091

When I pull enough $1 & $2 coins out of the ground, an AT Pro is certainly coming my way!

I think with the two gold rings the ACE 350 has found, it has already paid for it's-self.

Not sure about a sniper coil, I had one for the Garrett Master Hunter 7 ADS and I did not have much luck with that machine, it old when I acquired it and it always seemed to false on me.

T